Comparison of chicago sky blue (novel stain) with calcofluor white and potassium hydroxide mount for rapid diagnosis of dermatomycosis and onychomycosis in a tertiary care centre

Purpose: Dermatomycosis, the most common of mycotic infections, occur worldwide. In an epidemiological survey done in India, the prevalence of superficial fungal infection was 27.6%, out of which dermatomycosis was 75.6% and non-dermatmycosis was 24.4%. Rapid confirmation of dermatomycosis and onychomycosis is desirable because it allows the clinician to initiate appropriate therapy without delay. The existing modalities such as Calcofluor White stain requires fluorescent microscope whereas KOH is less sensitive compared to Calcofluor White stain. Aim of the study: To compare the novel contrast stain Chicago Sky Blue with the established methods such as Calcofluor White stain and KOH for the rapid diagnosis of dermatomycosis and onychomycosis. Materials and Methods: The infected nail clippings and skin scrapping were subjected to Chicago sky blue stain, Calcofluor White Stain and KOH mount. The microscopic findings were noted for the positive and negative results. Based on the results obtained, sensitivity and specificity of Chicago sky blue stain was assessed against Calcofluor White stain as reference method. Simultaneously, the diagnostic efficacy and cost effectiveness of Chicago sky blue, Calcofluor white stain and KOH mount was assessed. Results: Chicago Sky Blue stain is 100% sensitive in detecting dermatomycosis and 83.4 % in detecting onychomycosis whereas KOH mount is only 93% sensitive in detecting dermatomycosis and 66.7% in onychomycosis. Chicago Sky Blue stain is 100% specific in detecting dermatomycosis and onychomycosis whereas KOH mount is only 77% specific. Conclusion: Chicago Sky Blue stain was found to be highly efficacious, easy to perform and interpret as well cost-effective for detection of dermatomycosis and onychomycosis.